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手写服务器

手写服务器

作者: xin激流勇进 | 来源:发表于2019-04-22 17:37 被阅读0次
<?xml version="1.0" encoding="UTF-8" ?>

<web-app>
    <servlet>
        <servlet-name>login</servlet-name>
        <servlet-class>imooc.study.server.LoginServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>login</servlet-name>
        <url-pattern>/login</url-pattern>
        <url-pattern>/g</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>register</servlet-name>
        <servlet-class>imooc.study.server.RegisterServlet</servlet-class>
    </servlet>


    <servlet-mapping>
        <servlet-name>register</servlet-name>
        <url-pattern>/register</url-pattern>
        <url-pattern>/r</url-pattern>
    </servlet-mapping>
</web-app>
package imooc.study.server;

import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import java.util.List;

import static java.lang.Thread.currentThread;

public class XMLWeb {
    public static void main(String[] args) throws Exception {
        SAXParserFactory factory = SAXParserFactory.newInstance();
        SAXParser saxParser = factory.newSAXParser();
        WebHandler handler = new WebHandler();
        saxParser.parse(currentThread().getContextClassLoader().getResourceAsStream("web.xml"), handler);
        List<Entity> entityList = handler.getEntityList();
        System.out.println(entityList);
        List<Mapping> mappingList = handler.getMappingList();
        System.out.println(mappingList);

        WebContext webContext = new WebContext(entityList, mappingList);
        String className = webContext.getClz("/xxx");
        System.out.println(className);

        //根据反射 实例化对象
        Class<?> forName = Class.forName(className);
        Servlet o = (Servlet) forName.newInstance();
        o.service();
    }


}

package imooc.study.server;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

class WebHandler extends DefaultHandler {

    private Entity entity;
    private Mapping mapping;

    private List<Entity> entityList;
    private List<Mapping> mappingList;
    private String tag;
    private boolean isEntity;
    private boolean isMapping;

    public List<Entity> getEntityList() {
        return entityList;
    }

    public List<Mapping> getMappingList() {
        return mappingList;
    }

    @Override
    public void startDocument() throws SAXException {
        entityList = new ArrayList<>();
        mappingList = new ArrayList<>();
        isEntity = false;
        isMapping = false;
    }

    @Override
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
//        System.out.println();
//        System.out.println("start-->" + qName);
        tag = qName;
        if (qName.equals("servlet")) {
            entity = new Entity();
            isEntity = true;
        } else if (qName.equals("servlet-mapping")) {
            mapping = new Mapping();
            isMapping = true;
        }
    }

    @Override
    public void endElement(String uri, String localName, String qName) throws SAXException {
//        System.out.println();
//        System.out.println("end-->" + qName);
        if (qName.equals("servlet")) {
            entityList.add(entity);
            isEntity = false;
        } else if (qName.equals("servlet-mapping")) {
            mappingList.add(mapping);
            isMapping = false;
        }
        tag = null;
    }

    @Override
    public void endDocument() throws SAXException {
//        System.out.println(list);
//        System.out.println("stop-----");
//        System.out.println("============");
    }

    @Override
    public void characters(char[] ch, int start, int length) throws SAXException {
        String content = new String(ch, start, length);
//        System.out.println("content--->" + content);
//
//        if (Objects.equals(tag, "name")) {
//            person.setName(content);
//        } else if (Objects.equals(tag, "age")) {
//            person.setAge(Integer.parseInt(content));
//        }

        if (isEntity) {
            if (Objects.equals(tag, "servlet-name")) {
                entity.setName(content);
            } else if (Objects.equals(tag, "servlet-class")) {
                entity.setClz(content);
            }
        } else if (isMapping) {
            if (Objects.equals(tag, "servlet-name")) {
                mapping.setName(content);
            } else if (Objects.equals(tag, "url-pattern")) {
                mapping.addPattern(content);
            }
        }
    }
}

package imooc.study.server;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class WebContext {
    //k -> servlet-name v -> servlet-class
    private Map<String, String> entityMap;
    //k-> url-pattern v -> servlet-name
    private Map<String, String> mapingMap;

    public WebContext() {
    }

    public WebContext(List<Entity> entityList, List<Mapping> mapingList) {

        entityMap = new HashMap<>();
        mapingMap = new HashMap<>();

        for (Entity entity : entityList) {
            entityMap.put(entity.getName(), entity.getClz());
        }

        for (Mapping mapping : mapingList) {
            for (String pattern : mapping.getPattern()) {
                mapingMap.put(pattern, mapping.getName());
            }
        }

    }

    public String getClz(String pattern) {
        return entityMap.get(mapingMap.get(pattern));
    }
}

package imooc.study.server;

public interface Servlet {
    void service();
}

package imooc.study.server;

public class RegisterServlet implements Servlet {
    @Override
    public void service() {
        System.out.println("RegisterServlet");
    }
}

package imooc.study.server;

public class LoginServlet implements Servlet {
    @Override
    public void service() {
        System.out.println("LoginServlet");
    }
}

package imooc.study.server;

import java.util.HashSet;
import java.util.Set;

public class Mapping {
    private String name;
    private Set<String> pattern;

    public Mapping() {
        pattern = new HashSet<>();
    }

    public Mapping(String name) {
        this.name = name;
    }

    public void addPattern(String parttern) {
        pattern.add(parttern);
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public Set<String> getPattern() {
        return pattern;
    }

    @Override
    public String toString() {
        return "Mapping{" +
                "name='" + name + '\'' +
                ", pattern=" + pattern +
                '}';
    }
}

package imooc.study.server;

public class Entity {
    private String name;
    private String clz;

    public Entity() {
    }

    public Entity(String name, String clz) {
        this.name = name;
        this.clz = clz;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setClz(String clz) {
        this.clz = clz;
    }

    public String getClz() {
        return clz;
    }

    @Override
    public String toString() {
        return "Entity{" +
                "name='" + name + '\'' +
                ", clz='" + clz + '\'' +
                '}';
    }
}

package imooc.study.server.serverdemo;

import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Date;

public class Server {

    private ServerSocket serverSocket;

    public static void main(String[] args) {
        Server server = new Server();
        server.start();
    }

    public void start() {
        try {
            serverSocket = new ServerSocket(8000);
            receive();
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("server is error");
        }
    }

    public void receive() {
        try {
            Socket accept = serverSocket.accept();
            InputStream inputStream = accept.getInputStream();
//            BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
//            String data;
//            while ((data = reader.readLine()) != null) {
//                System.out.println(data);
//            }

            byte[] data = new byte[1024*1024];
            int len = inputStream.read(data);

            String header = new String(data, 0, len);
            System.out.println(header);

            OutputStream out = accept.getOutputStream();
//            BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outputStream));
//            writer.write("HTTP/1.1 200 OK\r\n");
//            writer.write("Content‐Type:text/html\r\n");
//            writer.write(String.format("Date:%s\r\n", new Date()));
//            writer.write("\r\n");
//            writer.write("<h1>hello<h1>");

            out.write("HTTP/1.1 200 OK\r\n".getBytes());
            out.write("Content‐Type:text/html\r\n".getBytes());
            out.write(String.format("Date:%s\r\n", new Date()).getBytes());
            out.write("\r\n".getBytes());

            FileInputStream fileInputStream = new FileInputStream("src/main/resources/login.html");
            int read;
            while ((read = fileInputStream.read()) != -1) {
                out.write(read);
            }

//            out.write("<h1>hello<h1>".getBytes());
            out.flush();
        } catch (IOException e) {
            e.printStackTrace();
            System.out.println("client connect error");
        }
    }

    public void stop() {

    }
}

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